View full sizeBenjamin Brink/The OregonianThe O'Reilly Open Source Convention -- OSCON -- is drawing more than 3,000 technologists from around the world to the Oregon convention center this week. Davide Dalle Carbonare traveled from northern Italy. He works with QualiPSo, an open source project funded by the European Union.

This week, Portland is once again at the center of open source technology.

More than 3,000 software developers from around the globe have descended on the Oregon Convention Center for the O'Reilly Open Source Convention -- OSCON -- one of the largest gatherings of its kind. It's also among Portland's biggest national conferences.

The conference started Monday, but the main program began Wednesday. Tim O'Reilly, chief executive of the company hosting OSCON, used his opening keynote to urge attendees to use technology to improve government.

"I've been really fascinated by the possibility of technology to help us reinvent government," he said. "I think that government, too, is a mechanism for collective action."

O'Reilly singled out Portland's CivicApps program as an example of such initiatives. Portland Mayor Sam Adams will give a brief keynote on that theme at OSCON on Friday.

Open source technology remains obscure to everyday computer users, but it powers sophisticated communications networks and mainstream devices like TiVo.

View full sizeBenjamin Brink/The OregonianMac Slocum, editor with OSCON organizer O'Reilly Media, interviewed Mike Hostelter, middle, and Jonathan Sharp of Web development company appendTo on the conference floor Wednesday. Their talk was webcast.

Unlike proprietary software like Microsoft and Apple's computer operating systems, open source programs can be customized by users. And it's often given away free.

That's a potent combination and has won legions of adherents, from major corporations including Google, Intel and IBM to freelance hackers who employ open source technology to handedly create powerful computer programs single-handedly.

Oregon has long been a home to a cluster of open source developers, including Linus Torvalds, who created and manages the Linux operating system.

But after six years in Portland, OSCON left last year for San Jose. It met with mixed reviews there and is now booked (

OSCON.pdf) to return to Portland through 2013. Conference organizer Allison Randal said attendance this year is strong.

"It's as good as our highest year so far," she said. "People are really happy to be back in Portland."